Conventionally, there has been widely used a component measuring device that measures a predetermined component in a body fluid such as blood or urine. With this type of component measuring device, there is known a colorimetric component measuring device in which a sample, for example, blood, is adhered to a test pad provided in a strip, and the degree of coloration caused by a reaction between a reagent impregnated in the test pad and the sample is optically measured (e.g., refer to Japanese Patent Application, JP 10-505676 W).
The colorimetric component measuring device is provided with a strip holder which includes a strip path (insertion hole) into which the strip is inserted, alight emitter which applies light to the test pad through a hole open on a wall surface of the strip path, and a light receiver which receives reflected light from the test pad. Further, biasing means for biasing the strip toward the hole is disposed at a position facing the hole, and a gray target (calibration member) is provided in the biasing means.
According to such a configuration, when a predetermined component in a body fluid is measured, it is possible to measure the light reflectivity of the gray target of the biasing means before the strip is inserted into the strip path and adjust (calibrate) the optical energy amount of the light emitter on the basis of the measurement result. Accordingly, it is possible to reduce measurement variations caused by aging of the optical system.